Silicon products.



A UNITED STAT-ES PATENT OFFICE.

. FRANK mm, or NIAGARA FALLS, NEW YORK, Assrenon r rnn'cAnnonUNnUM comrNY, or NIAGARA r'ALLs, NEW YORK, A coarortArron or IPENNSYLVANIA.

SILICON PRODUCTS.

No Drawing.

Specification of Letters Patent. Application filed March 4, 1912. serialNo. 681,828.

- Patented June 4, 1912.

To all whom it may concern:

Be it known that I, FRANK J. TONE, of Niagara Falls, Niagara. county,and State of New York, have invented a new and useful Improvement inSilicon Products, of which the following is a full, clear, and exactdescription.

My invention relates to a new and valuable product composed essentiallyof silicon, oxygen and carbon." The product is a sublimationor-condensation product made 1n an electric furnace operated with amixture of silica and carbon.

In making the product herein claimed, I prefer to use a chargeconsisting of 35 parts by weight of powdered coke, 54 parts by weightsilica sand and 7 parts by weight of sawdust. This charge is placed in agranular core resistance furnace,- preferably of the type well known inthe manufacture of silicon carbid and shown in U. S. Patent No.

' 560291, issued May 19, 1896. The-charge surrounds the horizontal core,which extends from one terminal of' the furnace to the other, and bymeans of which core it is possible to heat the surrounding charge to anydesired temperature up to the point where silicon carbid is dissociated..In connection with this resistance furnace, I provide in closeproximity to it and communicating with the core and zone of mixtureimmediately in contact with the core, a condensation chamber havingwalls provided with suitablerefractory material, preferably siliconcarbid. The condensation chamber is closed to the outside air andcommunicates only with the atmosphere of the furnace, so that the gasesand gaseous products, which form or are present in the zone next to thecore, can enter said chamber. The furnace is operated as a normalsilicon carbid furnace, and the operation is not carried to the pointwhere silicon carbid o y 1s ormed around the core, but is continueduntil some silicon carbid is decomposed, liberating silicon involatilized form. The atmosphere of the reaction zone of the furnaceconsists of carbon monoxid, silica and probably silica in reduced formas silicon or silicon monoxid.

A condensation product having very valu able properties, is formed inthe condensation chamber under the above named conditions, and isdescribed as follows: It has light green, greenish white or gray whitecolor. It has a soft felt-like and pliant structure and a resiliency orelasticity like felt, due ,probably'to its short fibrous texture. Itsapparent density is variable, .but is always verfi low being.approximately 0.15 and its real density is about 2.3. It is not actedupon by any of the mineral acids; however, hydrofluoric acid acts uponit, dissolving silica and leaving a residue, which is essentially asolid solution of silicon carbid in silica. The loss of silica bytreating -with pure oxygen at this temperature it is converted intosilica. As the product has a very high thermal resistivity and due toits refractory nature it is very valuable as a heat insulating material.On account of its fine texture it will form an eflicient material forair or gas filtration. It may also be used as an abrasive or polishingmaterial.

Without prejudice to any rights under this invention, the inventor makesthe following statement of his belief in regard to the material and itsmode of production. The product is believed to be a mixture of silicaand a solid solution of silicon carbid in silica. zone of the furnaceare silica, carbon monoxid and reduced silica, the latter being siliconor silicon monoxid. The reduced silica and carbon monoxid react formingsilica and silicon carbid and as these are produced they form a solidsolution. At the same time silica vapor exists in the furnace and theresulting product is a mixture of the solid solution of silica andsilicon carbid and silica. On account of its method of formation thechemical composition of.

The products from the reaction the' product may vary between very wide/limits, as the composition of the solid solution varies with therelative proportions of silicon and silicon monoxid in the reactionzone, and the percentage of silica vapor depends on the furnacetemperature. Consequently it can be seen that, by changing thecomposition of the furnace charge and the operating conditions of thefurnace, the

atmosphere inthe reaction zone. of the furr the fact that it is amixture of silica with another product which is apparently the solidsolution of silica in silicon carbid.

I claim:

l. A silicon oxygen carbon product of felt-like texture havlng anapproximate apparent density of 0.15 and a real density of about 2.3.

2. A silicon oxygen carbon product of felt-like texture, having anapproximate apparent density of 0.15, a real density of about 2.3 andcharacterized by high thermal resistivity and refractability.

3. A refractory condensation product, consisting of silicon-oxygen andcarbon in the proportion of approximately 50 parts of silicon, 44 partsof oxygen and 6 parts of carbon, having an approximate apparent densltyof 0.15, a real density of about 2.3, a pliant felt-like structure andbeing a poor conductor of heat. A

4. A refractory condensation product of silica and a solid solution ofsilicon carbid and silica, characterized by a real density of 2.3, apliant felt-like structure and having a high thermal resistivity. I

5. A silicon-oxygen-carbon condensation product of a reenish or graywhite color having a feltike liant structure.

In testimony w ereof, I have hereunto set my hand.

' FRANK J. TONE.

Witnesses:

J. I. RAFUSE, EARLE FINNEGON.

